Autonomous Hull Navigation

ABSTRACT

An autonomous hull robot navigation subsystem for guiding a hull robot on a hull of a vessel independent of external guidance devices includes a drive subsystem onboard the robot for driving and maneuvering the robot about the hull. A sensor subsystem onboard the robot senses an environmental characteristic. A navigation subsystem onboard the robot is responsive to the sensor subsystem and includes a processor. The processor utilizes the environmental characteristic to determine a position of the robot on the hull.

RELATED APPLICATIONS

This application claims the benefit of the following provisional patent applications, the contents of each of which are incorporated herein by reference in their entirety: U.S. provisional patent application Ser. No. 61/701,512, filed on Sep. 14, 2012; U.S. provisional patent application Ser. No. 61/701,517, filed on Sep. 14, 2012; U.S. provisional patent application Ser. No. 61/701,523, filed on Sep. 14, 2012; U.S. provisional patent application Ser. No. 61/701,529, filed on Sep. 14, 2012; U.S. provisional patent application Ser. No. 61/701,534, filed on Sep. 14, 2012; and U.S. provisional patent application Ser. No. 61/701,537, filed on Sep. 14, 2012.

This application is related to copending United States patent application Ser. No. ______, filed on ______(attorney docket no. 2865-11-2182-US-NP); Ser. No. ______, filed on ______(attorney docket no. 2865-11-2188-US-NP); Ser. No. ______, filed on ______(attorney docket no. 2865-11-2187-US-NP); Ser. No. ______, filed on ______(attorney docket no. 2865-11-2189-US-NP); and Ser. No. ______, filed on ______(attorney docket no. 2865-11-2192-US-NP), the contents of each of which is hereby incorporated by reference herein in their entirety.

This application is also related to the following copending United States patent applications: Ser. No. 12/313,643, filed on Nov. 21, 2008; Ser. No. 12/583,346, filed on Aug. 19, 2009; Ser. No. 12/586,248, filed on Sep. 18, 2009; Ser. No. 12/587,949, filed on Oct. 14, 2009; and Ser. No. 12/800,486 filed on May 17, 2010; the contents of each of which is hereby incorporated herein by reference in their entirety.

BACKGROUND

The structural integrity of a vessel hull is an important safety an economical concern. For example, frictional resistance due to buildup on or fouling of the hull by algae, sea grass, barnacles, and the like as a vessel moves through the water can increase the fuel consumption of the vessel. As an example, an added resistance of 30% due to moderate bio-fouling of a tanker hull can increase the fuel consumption of the vessel by up to twelve tons per day. The result is added cost to operate the vessel, as well as increased emissions. Monitoring of damage to the hull is useful in determining when and where repairs should be made.

A variety of methods are currently employed to lower the chance of bio-fouling and/or to rid vessel hulls of bio-fouling through cleaning, as well as to monitor the structural integrity of the hull. For example, typically, while the ship is dockside and/or during normal unlading conditions, the hull is periodically inspected manually by scuba divers. The cost of such an inspection effort is high. The type of inspection effort may need to be repeated at a predetermined period of months, such as every ten to twenty months or sooner, particularly if there is suspicion of damage to the vessel hull. To inspect the vessel hull, the hull often must first be cleaned. As a complication, however, some jurisdictions have made dockside cleaning illegal due to the toxicity of anti-fouling paint particles removed during cleaning, which can contaminate the water.

In response, robotic hull cleaners have been proposed. The “Hismar” consortium, for example, has proposed a robotic platform for hull cleaning during normal unlading conditions. The robot is magnetically attached to the hull when the vessel is stationary and is tethered to an operator control unit, a high pressure water source, a suction subsystem, and a power subsystem. Various other robots have also been proposed.

Despite some of their advantages over manual cleaning procedures, prior hull cleaning robots suffer from various shortcomings. For instance, most prior hull cleaning robots are connected or tethered to a cable and powered and controlled by an on-board power supply and control system and are able to operate only on a stationary vessel. Further, inspection techniques for determining the cleanliness of the hull are inefficient. Still further, navigation of such robots may be by remote manual navigation and rely on input of a human operator to guide the robot about the hull.

SUMMARY

An autonomous hull robot navigation subsystem for guiding a hull robot on a hull of a vessel independent of external guidance devices, in accordance with an example embodiment of the present technology, can include a drive subsystem onboard the robot for driving and maneuvering the robot about the hull. A sensor subsystem onboard the robot can sense an environmental characteristic. A navigation subsystem onboard the robot can be configured to be operable with and responsive to the sensor subsystem and include a processor. The processor can utilize the environmental characteristic to determine a position of the robot on the hull, which facilitates continuous navigation.

A method of autonomous hull robot navigation for guiding a hull robot on a hull of a vessel independent of external guidance devices, in accordance with an example embodiment of the present technology, can include sensing an environmental characteristic near the hull robot using a sensor subsystem onboard the robot. A position of the hull robot on the hull can be determined based on the environmental characteristic using a navigation subsystem onboard the robot, which is operable with and responsive to the sensor subsystem. The robot can be maneuvered about the hull using a drive subsystem onboard the robot based on the position of the hull robot.

A system for autonomous hull robot navigation on a hull of a vessel independent of external guidance devices, in accordance with an example embodiment of the present technology, can include a sensor onboard a hull robot configured to detect an environmental characteristic. A database onboard the hull robot can be configured to store information about the hull of the vessel, including correspondence information relating a position on the hull with the environmental characteristic detected by the sensor. A processor onboard the hull robot can be configured to compare the detected environmental characteristic with the correspondence information in the database to determine the position of the hull robot on the hull. The hull robot can thus navigate about the hull by continuously or periodically detecting environmental characteristics and comparing these for position determination.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a bottom perspective view of a hull robot in accordance with an embodiment of the present technology;

FIG. 2 is a top perspective cutaway view of the hull robot of FIG. 1;

FIG. 3 is a bottom perspective view of a hull robot in accordance with an embodiment of the present technology;

FIG. 4 is a block diagram of a hull robot system in accordance with an embodiment of the present technology;

FIG. 5 is a detailed view of the navigation and electronic subsystems of the hull robot system of FIG. 4;

FIG. 6 illustrates a vertical navigation path of a hull robot on a hull of a vessel in accordance with an embodiment of the present technology;

FIG. 7 is a perspective view of a symmetrical hull robot traveling orthogonal to a fluid flow field in accordance with an embodiment of the present technology;

FIG. 8 is a block diagram of a hull robot system including power scavenging, magnetic fixation, and a deployable skirt in accordance with an embodiment of the present technology;

FIGS. 9 a-9 c illustrate energy harvesting devices in accordance with embodiments of the present technology;

FIG. 10 is a flow diagram of a method of autonomous hull robot navigation for guiding a hull robot on a hull of a vessel independent of external guidance devices, in accordance with an embodiment of the present technology; and

FIG. 11 is a block diagram of a system for autonomous hull robot navigation on a hull of a vessel independent of external guidance devices, in accordance with an embodiment of the present technology.

DETAILED DESCRIPTION

Before the present disclosure is described herein, it is to be understood that this disclosure is not limited to the particular structures, process steps, or materials disclosed herein, but is extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.

DEFINITIONS

The following terminology will be used in accordance with the definitions set forth below.

As used herein, “robot body” is intended as a broad term to define one or more structural components (e.g., a frame, chassis, cover, etc.) capable of supporting one or more other components of a hull robot or its subsystems, and/or capable of providing covering and/or concealment of one or more components or subsystems of the hull robot.

As used herein, the singular forms “a,” and, “the” include plural referents unless the context clearly dictates otherwise.

As used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained. The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. For example, a composition that is “substantially free of” particles would either completely lack particles, or so nearly completely lack particles that the effect would be the same as if it completely lacked particles. In other words, a composition that is “substantially free of” an ingredient or element may still actually contain such item as long as there is no measurable effect thereof.

As used herein, the term “about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be “a little above” or “a little below” the endpoint.

As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary.

Example Embodiments

Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the technology is thereby intended. Additional features and advantages of the technology will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the technology.

It is noted in the present disclosure that when describing the system, or the related devices or methods, individual or separate descriptions are considered applicable to one another, whether or not explicitly discussed in the context of a particular example or embodiment. For example, in discussing an energy harvester configuration per se, the device, system, and/or method embodiments are also included in such discussions, and vice versa.

Furthermore, various modifications and combinations can be derived from the present disclosure and illustrations, and as such, the following figures should not be considered limiting.

FIGS. 1-3 show an example hull robot 10 with robot body 12 supporting combined turbine/generator units 32 a and 32 b. The turbines are responsive to fluid moving past the vessel hull when the vessel is underway, e.g., the turbine intakes are behind screen 30 and are responsive to fluid moving past the vessel hull. The turbines drive the generators which in turn charge battery pack 38. Electronic control module 40 is powered by battery pack 38 as are the motors and other power devices on-board robot 10. Typically, one motor drives, for example, gear 42 b which in turn drives gears 42 a and 42 c. In this way, cleaning brushes 36 a-36 d are operated. Another motor is typically associated with drive module 18 which both holds the robot on the hull and maneuvers the robot about the vessel hull. The motor system for drive module 18 may vary in design. For example, the turbines could directly drive module 18 (and/or brushes 36 a-36 d). Also, brushes 36 a-36 d may be driven or rotated in different directions. For example, FIG. 2 illustrates two sets of counter-rotating brushes 36 a-b and 36 c-d supported by the robot body 12, which are rotated using a belt and pulley system actuated by the motor 40 (which may be powered by power source 38). Any number of brushes or cleaning elements may be used to suit a particular application, such as a greater or lesser number of brushes. For example, a modified embodiment can include two counter-rotating brushes (see counter-rotating brushes 36 a-36 b in FIG. 3). The hull robot may include one or more drive modules.

The robot body 12 can include turbine intake vents 14 a and 14 b and cleaning brushes 16 a, 16 b, and 16 c behind an outflow vent. A magnetic drive belt 22 is typically disposed about rollers 21 a and 21 b as shown.

In the example shown, turbines 26 a and 26 b drive generators 28 a and 28 b, respectively, each including an rpm sensor or voltage sensor. By monitoring the output of each generator, any difference between the outputs of turbines 26 a and 26 b can be detected and minimized by turning the robot 10 on the hull. In still other examples, a sensor or the like can be used to determine the direction of fluid flow with respect to the robot body.

FIG. 4 illustrates an example including turbine subsystem 32 (including one or more devices actuatable by fluid flowing past the hull) and generator 70 which recharges power source 40. One or more motors such as motors 72 a and 72 b are powered by power source 40. Motor 72 a drives drive module 18 via drive train 74 a. The direction of travel of the robot can be reversed via electronic control subsystem 41 which is configured to reverse the direction of motor 72 a based on inputs, for example, from navigation subsystem 78 and/or communication subsystem 80. Electronic controller 41 is also powered by power source 40. Similarly, motor 72 b drives cleaning subsystem 82 (e.g., one or more brushes as described above) via drive train 74 b. Motor 72 b is also energized by power source 40. In other embodiments, the one or more motors may operate on the basis of a power source other than electricity. Motors are known, for example, that are fluid driven. The turbine subsystem then may pump fluid under pressure to the motors. If the cleaning subsystem is passive, e.g., a pad and/or a squeegee, motor 72 b and drive train 74 b would not be required. In other examples, the drive shafts of the turbines are mechanically linked to the cleaning brushes and/or drive module. Thus, the design of the motive subsystem for the drive module may vary.

FIG. 5 illustrates a more detailed view of the navigation subsystem 78 and the electronic subsystems 41 of FIG. 4 in accordance with various embodiments. One or more of the features described below and shown in the drawing may be included in a single robot. Also, any suitable combination of the features may also be implemented.

The navigation subsystem 78 can be used to determine the location of the hull robot about the hull and to assist in navigation of the hull robot. For example, the navigation subsystem can include a sensor or sensor subsystem in the form of a detector (e.g., gravity vector detector 115, pressure detector/sensor 120, flow field detector 125, acoustic energy (e.g., noise) detector 130, ultrasonic detector 135, and/or cleanliness detector 140) operable to detect a characteristic of the environment surrounding the hull robot, or in which the hull robot is operating, for use in identifying a position of the hull robot about the vessel hull. Thus, the robot can identify a position on the hull without receipt of external signals or devices.

A number of sensor subsystems or detectors and/or methods are described herein for use in the present technology. However, the concepts described herein are non-exhaustive examples, and many other implementations are also possible and are considered to be within the scope of this disclosure. Some of the examples provided may be able to perform the intended function independent of other sensing or detecting devices or methods, while others may be combined with others for more accurate or complete position identification or determination. A hull robot navigation subsystem may use one or more of the described technologies in any desirable combination. Some example methods for navigating the hull robot include use of a cleanliness detection system, use of gravity vectors (also referred to herein as “g-vectors”), use of water pressure or water flow fields, detection of noise or sound (acoustic energy), ultrasonic detection, and so forth. These are described in more detail below.

A hull robot system can include an onboard cleanliness detection system 140 as one of the electronic subsystems 41. Such systems can be used to perform a navigation function or position identification function in addition to the cleanliness detection function. For example, the hull robot may make any number of passes across the ship in cleaning the hull, analyzing the hull, determining a cleanliness level of the hull, and so forth. Each pass may be offset by the previous pass so as to substantially not maneuver over the same area of the ship again. In one aspect, the cleanliness detection system can use the last or just completed pass to guide a next pass. A database 145 onboard the hull robot can store path information or a path configuration of the robot. Thus, in operation, when the robot has traversed the hull a certain number of passes, a processor 150 can reference the database to identify approximately where on the hull the robot is currently located.

Alternately, one or more sensor subsystems or detectors within the navigation subsystem 78 can measure a distance traveled by the robot, or characteristics of the environment around the robot to determine an approximate location. This can take place concurrently with cleanliness detection operations as performed by the cleanliness detection subsystem (or other operations, such as an inspection operation). In one example, the navigation subsystem 78 or cleanliness detection subsystem 140 may utilize a detector to detect an edge of the ship. Thus, the detection of the edge of the ship can serve the purpose of identifying a location which is not part of the hull and need not be analyzed for cleanliness detection or inspection purposes, and also can be used to identify a relative position of the robot on the hull. For example, the detector for detecting an edge of the ship may comprise a magnet for detecting the presence of the metal hull, or a camera for optically detecting the presence of the edge of the hull. Various other detectors may also be used.

The navigation subsystem 78 can include a g-vector type sensor subsystem or detector 115. More specifically, the g-vector detector can be a gravitometer or gravimeter for detecting a direction of gravity. A ship or vessel generally may have a hull with a specific contoured shape. Different positions on the hull between a top and a bottom of the hull may be angled differently with respect to one another. A hull robot equipped with a gravimeter can detect a unique g-vector for substantially any vertical location about the hull. For example, a direction of gravity may remain substantially the same, but an orientation of the robot with respect to the direction of gravity may change as the robot traverses the hull. Thus, in some examples, the g-vector can be determined relative to an orientation of the robot, or more specifically to a longitudinal and/or lateral axis or angular orientation with respect to the detected direction of gravity. The unique g-vectors for the various vertical locations about the hull can be pre-determined and stored in a database that can be referenced when the gravimeter detects the direction of gravity with respect to a current robot position or orientation. Comparison of known g-vectors with presently detected g-vectors can assist in the detection of the position of the robot about the hull, and navigation of the robot about the hull.

A simple measurement of an individual g-vector may be sufficient to identify the approximate vertical position by reference to the unique g-vector values stored in the database. In some examples, the vertical position of the robot may provide sufficient information for a desired application. However, in other examples, a horizontal or lateral position may also be desired. While other technologies or sensors could be combined with the gravimeter to provide this information, the gravimeter itself can be configured to provide sufficient information to roughly estimate the lateral position as well. For example, the vertical change in slope of the hull contour may vary along a length of the hull. Thus, if the hull robot analyzes a change in vertical slope of the hull contour as the robot traverses the hull, the lateral position on the hull can be estimated in addition to the vertical position.

In a more specific example, rather than, or in addition to, use of the gravimeter, an accelerometer may be used to determine an orientation of the hull robot relative to the ship. The detected orientation data can be used similarly to the gravity data described above. In addition, the orientation data can be used to determine a lateral change in slope of the hull contour along the length of the vessel. Thus, if the hull robot analyzes a change in lateral slope of the hull contour as the robot traverses the hull, the lateral and/or vertical position on the hull can be estimated.

In another embodiment, fluid pressure (e.g., water pressure) in which the vessel is floating can be used to determine location information of the robot about the hull. The navigation subsystem 78 can include a water pressure type sensor subsystem or detector/sensor 120 supported about the robot that is configured to sense or measure pressure. The pressure generally will have a direct correspondence with a depth beneath a surface of the water. The sensor may operate in conditions where there is minimal turbulence in the water and/or rocking of the vessel, but pressure readings will be available in turbulent conditions, and/or when the vessel is rocking. Pre-determined pressure information can be generated and stored in a database onboard the robot for later comparison to facilitate identification of an approximate vertical position on the side of the vessel hull. In one aspect, with the robot and the pressure sensor submersed, when a pressure is detected, reference to the database using a processor can identify the current pressure and the associated approximate vertical position about the hull by comparing the current pressure to those stored. In another aspect, the pressure sensor, or one or more different sensors, can further be configured to detect a pressure out of water as well. Thus, the pressure sensor(s), alone or in combination if multiple sensors are present, can determine whether the robot is above or beneath (or at) the water level, as well as an approximate vertical position about the hull. In addition, the pressure sensor can also be configured to determine a distance the robot is away from the water level, with depth or pressure measurements corresponding to a distance above or below the water, wherein an at-the-water line pressure can be determined and used for comparison.

In accordance with another example, the navigation subsystem 78 is configured to detect one or more characteristics of a fluid flow field using a fluid flow field type sensor subsystem or detector 125. The fluid flow field detector 125 can be configured to measure fluid flow velocity or the rate of fluid flow. As such, various types of flow sensors or flow meters are contemplated. The fluid flow detector 125 can be supported about the robot in a manner so as to be able to sense or detect fluid flow. The fluid flow detector can be a stationary detector or a deployable detector. Exemplary types of flow detectors can comprise mechanical flow detectors, such as piston meter/rotary piston, rotameters, turbine flow meters, Woltmann meters, single jet meters, paddle meters, multiple jet meters, pelton wheels, oval gear meters, current meters, etc. Other types of flow detectors can comprise pressure-based meters, such as venture meters, orifice plate meters, Dall tubes, pitot tubes, multi-hole pressure probes, etc. Still other exemplary flow detectors can comprise optical detectors, such as laser-based detectors. Still other types can comprise thermal mass flow meters, electromagnetic-based detectors, ultrasonic-based detectors, coriolis flow meters, laser-based flow meters, and others. Moreover, one or more of these can be used in combination about the hull robot if necessary or desired.

In fluid dynamics the flow velocity, or velocity flow field, or flow rate of a fluid comprises a vector field which can be used to mathematically describe the motion of a fluid. The length of the flow velocity vector is representative of the flow velocity. Depending upon the configuration of the hull, the flow field about the hull may be different at various locations about the vessel hull. For example, the fluid dynamics of the water as it flows over the hull can vary from the front of the vessel to the back, and from the surface of the water to the bottom of the vessel. As such, fluid flow and/or fluid flow rate can be detected or measured at one or more locations about the hull. Pre-determined flow or flow rate information can be obtained and stored in a database for later reference and comparison in facilitating determination of a position of the robot about the hull when the flow field about the robot is detected.

In one aspect, the flow field detector can be an energy harvesting device, such as a turbine, water wheel, piezoelectric element, or the like, exposed to the flow of fluid. The energy harvested by the energy harvesting device can be interpreted as a function of location on the hull. In one aspect, because fluid flow can vary over the expanse of the hull, a local relative fluid flow can be measured or sensed to indicate a position of the robot on the hull. For example, the amount of energy harvested over a unit of time along a given path can be indicative of a force or speed or direction of fluid flow, which information can then be used to determine the position of the robot on the hull in a similar manner by comparing this currently obtained information with predetermined stored information.

The energy harvesting device may be a displacement energy extraction device configured to extract energy from the environment due to displacement of at least a displaceable member or component of the energy extraction device. For example, turbines, propellers, water wheels, flappers (e.g., a hinged extraction device that “flaps” as fluid flows past, wherein the “flapping” motion generates harvestable energy), piezoelectric elements and so forth may be displaced in the form of rotation, oscillation, flexing and so forth as a result of fluid flow past the robot in order to generate energy which may be harvested and used by the robot. The displaceable member may be turbines, propellers or the like which rotate about an axis defined by a rotor, or may be piezoelectric or other oscillation-based devices where the flexing, bending, or hinging component is the displaceable member.

In one example, the water wheel configuration may comprise a plurality of blades disposed about a rotor of the water wheel which cause rotation of the rotor when the fluid flows against the blades. In another example, the water wheel configuration may include a plurality of fluid containers or “buckets” disposed about the rotor of the water wheel and configured to capture fluid therein to cause rotation of the rotor.

In one example, the displacement energy extraction device may be an oscillation-based energy extraction device. Piezoelectric elements and flapper devices as described previously are examples of oscillation-based energy extraction devices configured to harvest energy based on an oscillating movement, or rather a movement back and forth between multiple different positions. The oscillation-based energy extraction device may be oscillateable in response to the fluid flow acting upon the oscillation-based energy extraction device.

In one example, a fluid flow path may exist in the robot body, which may be defined by structure of the robot body, to direct the fluid flow toward the displacement energy extraction device. In one example, the fluid flow path may be in the form of a tube for receiving fluid at one end and directing fluid toward the extraction device at another end. In another example, the fluid flow path may be a path defined by sides of the robot body or other structure for restricting, directing or otherwise affecting a direction of flow of the fluid.

In one example, the fluid flow path may exist without the robot body, or rather may be positioned outside of the robot body within the fluid flow field created by the passing water as a result of movement of the vessel as it is underway. The fluid flow path may be the flow of the fluid past the vessel as the vessel moves within the fluid. The fluid flow path may also be impacted by a shape of the robot body, which may cause the fluid to flow around the robot body. The energy extraction device may be operable to extract energy from the fluid flow about the vessel resulting from the motion of the vessel in the fluid. The hull robot may include a support structure for positioning and supporting the energy extraction device without the robot body such that the energy extraction device is in contact with the fluid flow outside the robot body.

Energy harvested may be useable by cleaning subsystems, drive subsystems or other subsystems to perform various different functionalities. For example, the cleaning subsystem may use the energy to operate a cleaning element configured to perform a cleaning function to clean the hull of the vessel. The drive subsystem may use the energy to power one or more drive elements configured to drive and maneuver the robot about the hull of the vessel.

Energy harvested using the extraction device may be used to directly power the robot or subsystems of the robot, or may be stored for later use, such as by storing generated power in a power supply or battery.

In examples where a hull robot is shaped or otherwise configured to receive fluid flow in a particular direction or at a particular portion of the robot, the hull robot may be optimized to maintain an orientation of the robot relative to the fluid flow to maximize energy harvested from the flow while driving and maneuvering the robot about the hull. For example, a maximal amount of energy may be harvested from the fluid flow when the fluid flows directly toward an energy extraction device or toward an opening which directs the fluid along a fluid flow path toward the energy extraction device. A fluid flow field detector may detect whether energy being harvested is maximized, but causing the robot to change orientation relative to the flow field surrounding the robot to determine whether a change results in an increase in energy harvested. If so, the flow field detector may cause the robot to maintain the changed orientation. If not, the flow field detector may cause the robot to alter the orientation of the robot, such as a return to the original orientation. In another example, a velocity of the flow may be detected using the fluid flow detector, which may provide an indication as to whether the energy extraction device is receiving the full velocity of the fluid due to the velocity of the motion of the vessel.

In accordance with another example, acoustic energy (i.e., noise or sound) can be detected and used to determine the robot location, and to facilitate in navigation of the robot about the hull. More specifically, the navigation subsystem 78 can make use of environmental characteristics or conditions in the form of existing or natural boat derived noise fiduciaries to identify an approximate location of the robot on the hull, and to facilitate navigation of the robot. In one exemplary embodiment, the navigation subsystem can include a microphone or other suitable acoustic energy type sensor subsystem or detector 130 for detecting naturally derived noise fiduciaries that are native to the vessel, such as those generated merely by operation of the vessel. As such, the vessel need not include specially designed noise generation systems, although these are also contemplated. In one aspect, detectable acoustic energy may be generated by the engine itself, propeller operation in the water, or by other systems onboard the vessel. In another aspect, detectable acoustic energy may be generated by the interaction of various vessel structural components as the vessel moves through the water (e.g., bow noise generated as the vessel displaces water during operation).

In addition to detecting the acoustic energy being generated, position correspondence data can also be determined and stored for later use. Position correspondence data can comprise information regarding the relationship of measured characteristics of the vessel and/or the noise fiduciaries to the position of the robot on the hull. For instance, the robot can be caused to maneuver about the hull under various operating conditions. Acoustic energy generated under such conditions can be detected and measured for later comparison. The acoustic energy provided by the various energy sources of fiduciaries as the vessel is operated will likely be generated at different frequencies, each of which can be measured or detected by the acoustic detector and distinguished so it can be determined which particular energy source is which at any given time. In a specific example, vessel speed can be determined (e.g., by monitoring the performance and/or output of the turbines (e.g., the rate the turbines are rotating, etc.)). At a given speed, say 15 knots, the volume of the acoustic energy from the various energy sources or fiduciaries (such as the bow, the engine and the propeller, which locations or positions are all known and fixed) can be detected and measured at various locations about the hull. This relationship information can then be stored in a database as part of the overall collection of position correspondence data. The process can be repeated until sufficient acoustic energy data is gathered at any desired number of vessel speeds. This position correspondence data can be compiled, stored and made accessible to the robot later for navigational purposes.

In operation, the navigation subsystem can use these (or any other) noise fiduciaries to determine the location of and navigate the robot about the hull by comparing currently detected acoustical energy to the pre-determined position correspondence data associated with the sources of the acoustic energy as stored. Using this technique, the noise fiduciaries can be used to navigate the robot about the hull. For example, vessel engine noise, noise generated from fluid contacting a portion of the bow of the vessel, and noise generated from operation of a propeller may provide noise fiduciaries having known audio frequencies, which fiduciaries may be used to identify a position of the robot and/or navigate the robot about the hull.

In other exemplary embodiments, non-native or non-naturally occurring systems, equipment, etc. associated with or otherwise located on or about the vessel at various locations may also be deployed to generate identifiable or detectable acoustic energy that can be detected by an acoustic detector for use in similar robot location determination and navigation techniques. For example, one or more dedicated noise generation systems outputting acoustic energy at different frequencies can be placed about the vessel at various locations, and position correspondence data can be gathered and stored for later use in determining the position of the robot, and for navigation.

In another exemplary embodiment, ultrasonic signals or ultrasonic inspection via an ultrasonic type sensor subsystem or detector 135 can be used to identify a position, and facilitate navigation of the robot about the hull and may be functional during operation of the vessel. Ultrasonic inspection is a form of non-destructive inspection. In ultrasonic inspection, very short ultrasonic pulse-waves with center frequencies ranging from 0.1-50 MHz can be directed into the hull from an ultrasonic emitter, from which the waves may be reflected and detected using an ultrasonic detector to identify an ultrasonic signature, which may be representative of internal flaws or a characterization of hull properties. For example, the hull properties may be detected as ultrasonic signatures, and some non-limiting examples of such hull properties may include one or more of a hull thickness, integrity of a weld on the hull, a crack in the hull, a fissure in the hull, a change in thickness of the hull, an irregularity of the hull, and so forth. In one example, ultrasonic inspection can be used to determine a thickness of the hull to, for example, monitor corrosion.

In ultrasonic inspection, an ultrasound transducer connected to a diagnostic machine (both of which may be included in the inspection robot) is passed over the hull. The transducer may be separated from the hull by a couplant. While oil as a couplant may be used in some examples, the couplant is preferably water, due to the likely immersion of the robot under water on the vessel in motion.

Methods or modes of receiving the ultrasonic energy or waveform can include reflection and attenuation modes. In the reflection mode (otherwise known as the pulse-echo mode), the transducer sends and receives pulsed ultrasonic waves. The ultrasonic waves are reflected off of the hull back to the receiver or diagnostic machine. Reflected ultrasonic waves result from an interface with the hull, such as with the back wall of the hull or an imperfection within the hull. The diagnostic machine can store the results in the form of a signal with an amplitude representing the intensity of the reflection and the distance of signal travel as determined by a speed of the ultrasonic signal and an amount of time from when the signal was emitted to when the signal was received at the receiver after reflecting from the hull.

In the attenuation mode (otherwise known as the through-transmission mode), a transmitter sends ultrasonic energy through one surface of the hull, and a separate receiver on another surface detects an amount of ultrasonic energy traveling through the hull. Imperfections or other conditions in the space between the transmitter and receiver reduce the amount of ultrasonic energy transmitted, thus revealing the presence of such imperfections or conditions. The couplant increases the efficiency of the process by reducing the losses in the ultrasonic wave energy due to separation between the surfaces.

Ultrasonic inspection can be highly penetrating, allowing the detection of flaws deep in the hull. Ultrasonic inspection enables the detection of extremely small flaws. Ultrasonic inspection may be performed using an ultrasonic inspection device, such as an ultrasonic detector 135, and can be used to estimate a size, orientation, shape and nature of a defect in the hull.

Ultrasonic technology, including the ultrasonic detector 135, can be implemented in the robot to create and store an ultrasonic map of the hull. The map may comprise a collection of ultrasonic signatures relating to various positions about the hull, which ultrasonic signatures can be collected and stored for later use. The ultrasonic signatures may represent an environmental characteristic detectable by the sensor subsystem (i.e., the ultrasonic detector in this example). In operation, as the robot traverses the hull and as the ultrasonic pulse-waves are directed at and reflected off the hull, a plurality of ultrasonic signatures may be obtained. These electronic signatures can be used to generate a map representative of various portions of the hull. Therefore, in subsequent operational scenarios, the hull robot can determine its position about the hull by deploying an ultrasonic detector and comparing the current electronic signatures to those in the map that are pre-determined and stored in the database. Indeed, reference to the electronic signatures and/or the map based on a current detected ultrasonic signature can identify a position of the hull robot on the hull and can be used in navigating the robot.

It is contemplated herein that specific navigational direction of the robot about the hull may be less of a concern for a robot deployed while the vessel is docked at port because the vessel is stationary and the robot is not subject to forces induced by water flow. However, operation of the hull robot when the vessel is underway and in motion about the vessel, such that a flow field is created about the hull robot, may be more of a concern as this subjects the robot to additional forces as the passing water acts on the robot, and particularly the surfaces of the body of the robot. Therefore, to minimize or at least reduce the forces acting on the robot as caused by the passing water, rather than navigating about the hull along various horizontal paths, the robot may be configured to navigate along the hull of the vessel about vertical paths, as shown in FIG. 6 (e.g., paths extending between a bottom of the hull to a top of the hull even though the path may not be necessarily orthogonal to the surface of the water due to the hull configuration (as viewed from a front or rear view of the vessel and hull). In this way, energy can be conserved because the robot is not constantly working against the direction of the fluid flow on every other pass along the hull as it would when following a horizontal path about the hull (path extending from front to back of the hull). As a result, smaller and less-expensive drive motors may be used to drive the robot. In addition, traversing along vertical paths, the robot can navigate up and down, working its way from back to front or front to back, whichever is preferred. The vertical path can comprise a route that is transverse (e.g., orthogonal or approximately orthogonal) to the direction of fluid flow about the hull or to a surface of the fluid in which the vessel is operating. Traversing the hull in vertical or substantially vertical paths can reduce the energy expenditures of the robot as greater levels of efficiency are obtained over traversing horizontal paths.

Moreover, in these situations, the energy harvested can be a function of where the robot is on the hull, and the associated water flow field at that location. Indeed, the fluid flow field at any particular location about the vessel hull can be measurable and used further, such as for determining the location of the robot about the hull (comparing a measured flow field parameter to one or more pre-determined and stored parameters).

It is contemplated herein that the robot can be configured to navigate vertical paths along the hull in still a more efficient manner by employing a hull robot configuration where the robot (and particularly the robot body) is designed to be more hydrodynamic in a particular direction. More specifically, in some exemplary embodiments, the robot body can be hydrodynamically tuned in a direction transverse (e.g., orthogonal, or at least offset at some angle) to a direction of travel of the robot and/or a direction of functionality (e.g., cleaning, inspecting, etc.) of the robot, which hydrodynamically tuned direction is in the direction of fluid flow, such that the hydrodynamics of the robot while being maneuvered in the direction of travel are enhanced. Stated differently, the robot can comprise a configuration in which the robot body is tuned to be hydrodynamic in the direction of fluid flow, even though the hull robot may be caused to traverse the hull in a direction that is not necessarily in line with the fluid flow (e.g., transverse to the direction of fluid flow). For example, in an embodiment in which the robot is configured to operate about the hull in a vertical direction, as discussed above, the robot, and particularly the robot body, can comprise hydrodynamics that are tuned to be optimally efficient with the flow field while the robot faces or navigates in a direction orthogonal to or at an incline with the flow field. FIG. 7 illustrates a robot with a robot body 160 configured for hydrodynamically efficient travel in a vertical direction 165 about the hull of the vessel, which direction is orthogonal to a direction of a flow of fluid 170, or fluid flow field. In this embodiment, the robot body comprises an outer surface being hydrodynamically tuned along a lateral axis (which axis is parallel to or in line with a direction of fluid flow) in a direction ninety degrees from a longitudinal axis (which axis is parallel to or in line with a vertical travel direction), wherein the robot is further configured to travel in a direction parallel to the longitudinal axis. In this embodiment, the robot could traverse the hull of the vessel in a vertical direction, while still having enhanced hydrodynamics in the direction of the flowing fluid. The robot body in the tuned hydrodynamic direction may result in the fluid flow (resulting from motion of the vessel) over and about the robot body for enhanced efficiency of driving and maneuvering of the robot in the vertical direction.

With continued reference to FIG. 7, in another exemplary embodiment the hull robot, and particularly the body 160 of the hull robot, may be configured with a symmetrical shape (along any axis) to more efficiently facilitate movement of the robot about the vessel hull (e.g., in a bi-directional manner). For example, the robot body can be symmetric along a longitudinal axis extending between longitudinal sides (e.g., front to back) of the robot body. In addition, the hydrodynamics of the robot may be tuned to be optimally efficient along the longitudinal axis. Therefore, the robot can maneuver about the hull in a horizontal bi-directional manner with efficiencies provided in both directions rather than in only one direction. Of course, the robot can also be configured to be symmetric (and the hydrodynamics tuned) along a lateral axis extending between lateral sides of the robot body, along both longitudinal and lateral axes, along one or more axes other than longitudinal and/or lateral axes, and so forth to facilitate enhanced efficiency bi-directional driving of the hull robot about multiple axes having different orientations.

In one example, the robot body may comprise a semispherical shape with a substantially infinite number of axes of symmetry (e.g., radially symmetrical). Providing a symmetrical configuration allows the robot to be operated to clean and extract energy efficiently while operating in a bi-directional manner while facing the same direction (i.e., operating without having to turn around). Of course, the hull robot can turn around upon detecting an edge of hull and face an opposite direction, if desired.

As discussed above, the robot may be configured to drive in a direction along the longitudinal axis of the robot such that a fluid flow transverse to the longitudinal axis is against a lateral side of the robot body. The robot may be tuned or configured with the hydrodynamic configuration in a direction substantially parallel with a lateral axis extending between the lateral sides of the robot body, which lateral sides may extend between the longitudinal sides. Furthermore, an inlet may be formed in or along at least one lateral side of the robot body for receiving the fluid flow and for generating a fluid flow path within the robot body. A fluid flow path within the robot body may be generated from fluid being received in the inlet. The fluid flow path may be at least partially defined by structure within the robot body, such as the side walls of the robot body, a tube or pipe provided for fluid to flow through, and so forth. As described in this disclosure, the robot may comprise an energy extraction device 161, which, in this embodiment, may be supported about the robot body and oriented or tuned to be operable with the inlet and within the fluid flow path 171 to generate energy usable by the robot to perform various functions, such as driving, cleaning, and so forth. Similar to a shape of the robot body or an orientation of the inlet, the energy extraction device may be oriented and tuned in the tuned hydrodynamic direction. Tuning the energy extraction device in this direction may result in a maximized amount of energy or power which may be harvested by the energy extraction device.

In practice, efficient operation of a hull robot about a hull of a vessel may be enhanced by configuring the robot body with the hydrodynamic configuration tuned in a direction transverse to a direction of travel of the robot, and substantially in a direction of fluid flow resulting from motion of the vessel within a fluid; and configuring a drive subsystem onboard the robot to maneuver the robot about the hull of the vessel in a direction transverse to a direction of the flowing fluid to enhance the efficiency of the robot within the fluid flow. More specifically, the robot may be maneuvered in a direction substantially orthogonal to the direction of the flowing fluid (i.e., in a vertical direction) and the robot may be maneuvered in a substantially bi-directional manner to avoid turning the hull robot around, such as when an edge of the vessel is reached (e.g., a top or bottom of the hull of the vessel when the robot navigates along substantially vertical paths, such as by maneuvering the hull robot up and down the hull of the vessel while moving from a front of the ship towards a back of the ship).

As an example method of enhancing efficient operation of a hull robot, a hull robot may be configured to comprise a drive system operable to maneuver and drive the hull robot about a hull of a vessel along an axis extending from one of a top and bottom of the hull. A robot body of the hull robot may be configured to comprise a longitudinal axis extending between longitudinal sides of the robot body and a lateral axis extending between lateral sides of the robot body, the drive subsystem being configured to drive the robot in a direction along the longitudinal axis. An inlet may be formed along at least one of the lateral sides of the robot body, where fluid received in the inlet generates a fluid flow path within the robot body as tuned in the direction of the fluid flow. An energy extraction device may also be provided which is supported about the robot body, the energy extraction device being operably positioned within the fluid flow path.

As the robot traverses the hull, it may be desirable to stop movement, at least temporarily, and to secure the robot about the hull, such as due to water turbulence, completion of a task, or any of a variety of other reasons. In such situations, the hull robot can comprise a fixation system or device operable to secure the hull robot to the hull of the vessel more securely than with the general securing device (i.e., the magnetic track). One example technology for securing the robot to the hull, such as when the hull robot is parked on the hull, includes magnetic fixation. In this example, the robot may be configured to utilize or deploy a magnetic fixation system or device operable with the robot body and independent of the drive subsystem which incorporates much stronger or much more aggressive magnets than are used with the drive subsystem and which are caused to selectively engage the hull than those that are used to keep the robot secured to the hull when the robot is driving about the hull. The magnetic fixation device may be actuatable to securely maintain a position of the robot relative to the hull. For example, switchable magnets that are supported about the underside of the robot, but that are independent of the tracks, may be used. These can be selectively actuated, such as when the speed of the drive subsystem approaches zero or when the drive subsystem is inactive or otherwise not driving or maneuvering the robot about the hull. One or more magnetic fixation devices may be employed, such as one or more switchable magnets may be included in the magnetic fixation device, to secure the robot relative to the hull. The magnetic fixation devices may be positioned about the robot body, such as at opposing ends or sides of the robot body, at corners of the robot body, or in any other suitable position or configuration.

In another example, the stronger magnets can be incorporated into tracks or into wheels, but with separate magnetic systems from the tracks or wheels that can be deployed. Such a system can be designed to secure the robot in place. Example implementations of switchable magnets are described in U.S. application Ser. No. 12/587,949, which is incorporated herein by reference, as set forth above. Any of a variety of magnet types may be used, such as, for example, electromagnets which are switchable on and off, or permanent magnets which may be switchable by movement or rotation of the magnets. FIG. 8 illustrates a hull robot 175 with a switchable (i.e., rotatable) magnet 187 actuatable by an actuator 185 via an arm 189, the actuator being powered by an onboard battery or generator, or powered directly by drive subsystem (i.e., a magnetic belt 194). The arm can further be movable or telescoping in order to move the magnet closer or farther from the hull.

The magnetic fixation device may operably restrict maneuvering of the robot by the drive subsystem when securely maintaining the position of the robot relative to the hull. The magnetic fixation device may have an attachment configuration for restricting movement of and securing the robot about the hull, and may further have a non-attachment configuration which enables the drive subsystem to maneuver the robot about the hull of the vessel when not securely maintaining the position of the robot relative to the hull.

Also, various technologies can be used to assist in more securely maintaining robot attachment to the vessel while the robot is moving about the hull. Some of these examples will now be described.

In one aspect, passing water to can be used to assist in maintaining the hull robot on the hull. The hull robot may be configured with a series of ports that receive passing water. Some of these ports may be used to turn turbines and the like to power the robot, as has been described above. Some of the ports may provide outlets for water which flows into the robot and may generally not be a water intake. Fluid flow along the surface of the robot body can flow over the outlet and create a low pressure area at the outlet that draws water out from inside the robot. Thus, the water pressure inside or under the robot can be reduced as compared with the water pressure on the outside of the robot body, urging the robot body against the hull. Providing a robot body with such a configuration facilitates suction against the hull surface. A partial vacuum can thus be created within the hull robot about the surface of the vessel. In some embodiments, the robot need not be fully sealed against the hull in order to create a sufficient pressure difference to assist in securing the hull robot to the hull.

In another aspect, the hull robot may be more securely attached to the hull using active suction fixation. In one aspect, the hull robot can be configured to scavenge power to power the active suction fixation. In an example shown in FIG. 7, the hull robot 175 may include a deployable skirt 180 or other structure that can be deployed using a motor 182 or gearing to create at least a partial seal against the hull, whereupon water within the robot can be actively pumped out and at least a partial vacuum (or at least low pressure area) created. The pump can be powered by scavenging passing water much the same way power is provided by the turbines. The active suction fixation can also be used in combination with magnetic fixation, hydrodynamic force, or other means of securing the hull robot to hull.

As the robot is on the surface of the hull, passing water, or fluid flowing relative to the vessel or robot, can pass through and over the hull robot body. The passing water can be used with power scavenging systems, such as the turbines described above, or any other suitable power scavenging device, to power the robot. In one aspect, power scavenging systems can be optimized by enabling the power scavenging system 198 to extend or be extendable to reach outside the hull robot body, and beyond a boundary layer of the passing fluid to achieve a more consistent or constant input of passing water. Indeed, a boundary layer may create an inconsistent velocity profile. Getting outside the boundary layer can subject the power scavenging system to a more uniform velocity profile that provides a more consistent input. The power scavenging systems can be configured to be dynamically adjustable to various positions thereof with respect to the robot and the direction and strength of the fluid flow field using an actuator 196 to obtain the proper or desired position to obtain consistent flow input, and thus consistent power scavenging. For example, a support structure for supporting the power scavenging device (e.g., an energy extraction device) at a position without the robot body and/or beyond a boundary layer of the fluid flow may be retractable to draw the power scavenging device to a position within the robot body. In other words, the power scavenging device may be supported about the robot, and may be retractably extendable (i.e., moveable from a retracted position into an extended position, and vice versa) to without the body of the robot to begin extracting the energy.

Some power scavenging systems have been described in the patent applications related to the current application, which applications are identified in the “Related Applications” section of this document. Other power scavenging systems are also contemplated, such as oscillation based devices or systems. For example, as shown in FIG. 9 a, a flapper device 250 can be supported on the robot, wherein the flapper device 250 can be configured to extend from the robot to be positioned to receive or engage the passing water. The flapper device 250 can be supported about a rotating device 252 (e.g., a hinge) to orient the flapper device with the passing water. The flapper device can further comprise, or can otherwise be associated with, an energy generator 261. In operation, passing water causes the flapper device to oscillate, and to generate power via the generator, which can be extracted with extraction electronics 263 and used to power various components of the robot or can be stored in an on-board battery 265 for later use.

In another example shown in FIGS. 9 b-9 c, the flapper device 255 can be fixed about the hull robot rather than configured to rotate. In this example, the flapper device 255 can incorporate one or more piezoelectric elements configured to flex and oscillate at a flexible portion 260. Oscillation of the flapper caused by the passing water can cause the piezoelectric element(s) to generate a usable electric signal that can be used to power devices and/or charge batteries.

Still other types of power scavenging systems are contemplated, such as rotation-based energy scavenging devices or systems similar to the turbines or propellers shown in FIGS. 1-3, and described above. Other exemplary rotation-based extractors can comprise water wheels (e.g., a Pelton wheel), which can rotate about an axis and which can comprise a rotor assembly. The rotor assembly can include a plurality of blades or buckets situated or disposed about a rotor. The passing water can then impart rotational energy to the rotor as it contacts the blades or buckets.

In some embodiments, passing water can also be used to directly operate cleaning systems or elements onboard the robot. Directly powering the cleaning systems or elements using passing water can eliminate the use, cost, and complexity of electric motors. For example, brushes or other cleaning elements can be mechanically coupled to an energy extraction device in the form of a water wheel 192 or another scavenging or extraction device which is configured to power and turn the brushes. In this embodiment, the energy extraction device supports the one or more cleaning elements (brushes) thereon, such that actuation of the energy extraction device functions to actuate a cleaning function that can be carried out by the energy extraction device. For example, as water passes over the hull of the vessel due to the vessel being in motion as it is underway, the resulting fluid flow can actuate the water wheel, thus causing the brushes supported thereon to rotate. These can be caused to contact the hull surface to perform a cleaning function. Alternatively, the scavenging device can comprise a direct mechanical connection (e.g., direct drive train) to the drive subsystem, wherein passing water operates or activates the energy extraction or scavenging device, which then directly powers the drive subsystem 194 (FIG. 8). Other non-motorized cleaning systems or elements that utilize the passing water to be powered or actuated are also contemplated even though not specifically described herein or shown in the drawings. Nonetheless, such devices or elements will be apparent to those skilled in the art upon reading the disclosure herein.

Essentially, all systems and/or devices used to scavenge electrical power can be incorporated into the hull robot and used to convert passing water to mechanical output. Thus direct powering of systems can be enabled, as opposed to using an intervening motor. Systems may still implement a transmission of some kind to achieve a desired torque, as will be recognized by those skilled in the art. Furthermore, the robot can comprise a governor to limit a maximum RPM of the brushes, Pelton wheel, or any other component used.

In other embodiments, passing water can turn a generator to be able to decrease a size of a motor in the robot. The generator can also be configured to charge a battery. Smaller motors may be used when the robot is operating above the water since the robot will not be subject to fluid flow. In one aspect, the battery can be charged when the robot is below water to provide power to the various cleaning, navigation and/or drive subsystems when the robot is above and/or out of the water.

In one aspect, a velocity threshold may exist for passing fluid to actuate drive subsystems, cleaning subsystems, energy extraction devices (e.g., power scavenging devices) and so forth. A velocity of passing fluid may be a result of the vessel to which the hull robot is attached being in motion at a velocity meeting or exceeding a pre-determined velocity or the velocity threshold.

Referring to FIG. 10, a flow diagram of a method of autonomous hull robot navigation for guiding a hull robot on a hull of a vessel independent of external guidance devices is illustrated in accordance with an example embodiment of the present technology. The method includes sensing 310 an environmental characteristic on or about the vessel hull using a sensor subsystem onboard the robot. A position of the hull robot on the hull can be determined 320 by detecting the environmental characteristic using a navigation subsystem onboard the robot, which is responsive to the sensor subsystem. The robot can be maneuvered 330 about the hull using a drive subsystem onboard the robot based on a current position of the hull robot.

In one aspect of the method, sensing the environmental characteristic comprises sensing a cleanliness of the hull; and maneuvering the robot comprises maneuvering the robot to a less clean position on the hull when a current cleanliness is greater than a predetermined threshold. In other words, the robot can be configured to sense hull cleanliness and can be caused navigate to areas needing to be cleaned. In this aspect, the interface between the cleaned and yet-to-be-cleaned surface area on the hull represents a fiduciary that can be utilized to guide the robot, such as to clean the area adjacent the most recently cleaned area of the hull.

In one aspect of the method, sensing the environmental characteristic comprises sensing a direction of gravity relative to the robot; and determining the position of the hull robot comprises determining a vertical position of the robot on the hull based on a previously determined unique gravity vector corresponding to a position on the surface of the hull, as described above.

In one aspect of the method, sensing the environmental characteristic comprises sensing a fluid pressure or an acoustic characteristic of or near the hull, as described above. For example, sensing the environmental characteristic may comprise detecting an edge of the vessel to which the robot is attached. When an edge of the vessel is detected, the robot may change direction, such as by turning or moving in reverse.

In another example, sensing the environmental characteristic may comprise sensing a paint characteristic about the hull using a paint sensor subsystem. The navigation subsystem may be responsive to the paint sensor subsystem to facilitate navigation based on the paint characteristic. For example, the paint characteristic may be the presence or lack of paint. Such presence or lack of paint, particularly where a defined area is detected with or without paint, may be used to determine a position of the robot about the hull for navigation purposes, such as by identification of specific characteristics of the particular area which distinguish the area from other painted/non-painted areas of the ship. In another example, the presence or lack of paint may be used when the hull robot is configured to paint the hull of the vessel. The robot can detect whether paint is present to determine whether to paint the portion of the hull at which the robot is positioned. In another aspect, the paint characteristic may be a freshness of a coat of paint, which may be determined by reflectivity, brightness, smudging and so forth. The presence or lack of paint, as well as the freshness of the coat of paint may be detectable optically, such as by using an optical detector (i.e., a camera). Coloration, reflectivity, brightness, and so forth may be programmed into logic processed by a processor causing the camera to capture images and to paint the hull of the vessel, in order to determine the paint characteristic for navigation, painting or any other suitable purpose.

In one aspect, the method further includes scavenging energy from a flow of fluid past the robot, and maintaining an orientation of the robot relative to the flow of fluid to maximize energy harvested from the flow while the robot maneuvers along substantially vertical paths, as described above.

In one aspect, the method further includes fixing a position of the robot relative to the hull when the robot is not being maneuvered using a fixation device independent of a drive subsystem of the robot, as described above.

Referring to FIG. 11, a system 400 for facilitating autonomous hull robot navigation about a hull of a vessel independent of external guidance devices is illustrated in accordance with an example embodiment of the present technology. As shown, the system includes a sensor 410 located onboard a hull robot and configured to detect an environmental characteristic. A database 415 onboard the hull robot can be configured to store information about the hull of the vessel, including correspondence information relating a position of the robot on the hull with the environmental characteristic detected by the sensor. A processor 420 onboard the hull robot can be configured to compare currently detected environmental characteristic information with the correspondence information in the database to determine the position of the hull robot on the hull, and to facilitate navigation.

The system can include a memory 425 onboard the robot including data concerning the configuration of the hull and a desired path of travel for the robot. In one aspect, the memory may be a non-transitory computer readable storage media. In another aspect, the memory may compress random access memory (RAM). In yet another aspect, the memory may comprise both the non-transitory media and the RAM and the detected characteristic may be stored in the RAM while the stored characteristic (i.e., the correspondence information) is stored on the non-transitory media. The processor can access both the RAM and the non-transitory media to compare the data, according to computer readable program instructions, to identify the position of the robot about the hull.

The methods and systems of certain examples may be implemented in hardware, software, firmware, or combinations thereof. The methods disclosed herein can be implemented as software or firmware that is stored in a memory and that is executed by a suitable instruction execution system (e.g., a processor). If implemented in hardware, the methods disclosed herein can be implemented with any suitable technology that is well known in the art.

Also within the scope of this disclosure is the implementation of a program or code that can be stored in a non-transitory machine-readable medium to permit a computer or processor to perform any of the methods described above.

Some of the functional units described in this specification have been labeled as modules, in order to more particularly emphasize their implementation independence. The various modules, engines, tools, etc., discussed herein may be, for example, software, firmware, commands, data files, programs, code, instructions, or the like, and may also include suitable mechanisms. For example, a module may be implemented as a hardware circuit comprising custom VLSI (very large scale integration) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.

Modules may also be implemented in software for execution by various types of processors. An identified module of executable code may, for instance, comprise one or more blocks of computer instructions, which may be organized as an object, procedure, or function. Nevertheless, the executables of an identified module need not be physically located together, but may comprise disparate instructions stored in different locations which comprise the module and achieve the stated purpose for the module when joined logically together.

A module of executable code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within modules, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices. The modules may be passive or active, including agents operable to perform desired functions.

While the forgoing examples are illustrative of the principles of the present technology in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the technology. Accordingly, it is not intended that the technology be limited, except as by the claims set forth below. 

1. An autonomous hull robot navigation system for guiding a hull robot on a hull of a vessel independent of external guidance devices, comprising: a drive subsystem onboard the robot for driving and maneuvering the robot about the hull; a sensor subsystem onboard the robot configured to sense an environmental characteristic; and a navigation subsystem onboard the robot and responsive to the sensor subsystem, the navigation subsystem being configured to determine a position of the robot on the hull and to facilitate navigation based on the environmental characteristic.
 2. The system according to claim 1, further comprising a memory onboard the robot including data concerning the configuration of the hull and a desired path of travel for the robot.
 3. The system according to claim 1, wherein the sensor subsystem comprises a cleanliness detection system, and the environmental characteristic near the robot is a cleanliness of the hull, and wherein the navigation subsystem is configured to control the drive subsystem to maneuver the robot to a less clean position on the hull when a current position cleanliness is greater than a predetermined threshold.
 4. The system according to claim 1, wherein the sensor subsystem comprises a cleanliness detection system, and the environmental characteristic near the robot is an interface between a recently cleaned portion of the hull and a yet-to-be-cleaned portion of the hull.
 5. The system according to claim 1, wherein the sensor subsystem comprises a gravity-vector detector configured to sense a direction of gravity relative to the robot, wherein the hull configuration includes a continuously inclining surface, and wherein the navigation subsystem is configured to determine a vertical position of the robot on the hull based on a unique gravity vector corresponding to a position on the continuously inclining surface.
 6. The system according to claim 1, wherein the sensor subsystem comprises a pressure sensor configured to sense the fluid pressure about any given location about the hull.
 7. The system according to claim 1, wherein the sensor subsystem comprises a flow field detector.
 8. The system according to claim 1, wherein the sensor subsystem is an acoustic detection subsystem configured to detect acoustic fiduciaries.
 9. The system of claim 8, wherein the acoustic fiduciaries comprise at least one of vessel engine noise, noise generated from fluid contacting a portion of the hull of the vessel, and noise generated from operation of a propeller.
 10. The system of claim 8, wherein the noise fiduciaries comprise known audio frequencies specific to identified portions of the vessel.
 11. The system according to claim 1, wherein the sensor subsystem comprises an ultrasonic hull signature detector.
 12. The system according to claim 1, further comprising an energy harvesting device for harvesting energy generated by movement of the hull through a fluid to provide power to at least one of the autonomous hull robot navigation system, the drive subsystem, the sensor subsystem, and the navigation subsystem.
 13. The system according to claim 1, further comprising a power scavenging system for converting energy from fluid flow into usable mechanical or electrical power.
 14. The system according to claim 13, wherein the power scavenging system is extendable to a region outside of the robot at least beyond a boundary layer of the passing fluid.
 15. The system according to claim 1, wherein the drive subsystem is configured to maneuver the robot primarily along vertical paths on a surface of the hull in a direction approximately orthogonal to a direction of flow of a fluid past the hull, wherein the sensor subsystem comprises a flow field detector, and the drive subsystem is configured to maintain an orientation of the robot relative to the flow of the fluid while the robot maneuvers along the vertical paths to maximize energy harvested from the flow.
 16. The system according to claim 1, further comprising a switchable permanent magnetic fixation device independent of the drive subsystem and configured to securely maintain a position of the robot relative to the hull when the navigation subsystem is not controlling the drive subsystem to maneuver the robot.
 17. The system according to claim 1, wherein the environmental characteristic comprises an edge of the vessel.
 18. The system according to claim 1, wherein the sensor subsystem comprises an ultrasonic inspection device and the environmental characteristic comprises an ultrasonic signature of a portion of the hull of the vessel.
 19. The system according to claim 18, wherein the ultrasonic signature includes at least one of a hull thickness, integrity of a weld on the hull, a crack in the hull, a fissure in the hull, a change in thickness of the hull and an irregularity of the hull.
 20. The system according to claim 18, wherein the ultrasonic inspection device is functional during operation of the vessel and comprises an ultrasonic emitter configured to emit an ultrasonic wave and an ultrasonic detector configured to detect a reflected ultrasonic wave reflected off of the hull, the reflected ultrasonic wave useable to identify the ultrasonic signature.
 21. A method of autonomous hull robot navigation for guiding a hull robot on a hull of a vessel independent of external guidance devices, comprising: sensing an environmental characteristic near the hull robot using a sensor subsystem onboard the robot; determining a position of the hull robot on the hull based on the environmental characteristic using a navigation subsystem onboard the robot which is responsive to the sensor subsystem; and maneuvering the robot about the hull using a drive subsystem onboard the robot based on the position of the hull robot.
 22. The method according to claim 21, wherein sensing the environmental characteristic comprises sensing a cleanliness of the hull, and wherein maneuvering the robot comprises maneuvering the robot to a less clean position on the hull when a current position cleanliness is greater than a predetermined threshold.
 23. The method according to claim 21, wherein sensing the environmental characteristic comprises sensing an interface between a recently cleaned portion of the hull and a yet-to-be-cleaned portion of the hull.
 24. The method according to claim 21, wherein sensing the environmental characteristic comprises sensing a direction of gravity relative to the robot, and determining the position of the hull robot comprises determining a vertical position of the robot on the hull based on a unique gravity vector corresponding to a position on a continuously inclining surface of the hull.
 25. The method according to claim 21, wherein sensing the environmental characteristic comprises sensing at least one of a pressure of fluid proximal to the robot and an acoustic characteristic of or near the hull.
 26. The method according to claim 21, further comprising harvesting energy from a flow of fluid past the robot, and maintaining an orientation of the robot relative to the flow of fluid to maximize energy harvested from the flow while the robot maneuvers along substantially vertical paths.
 27. The method according to claim 21, further comprising fixing a position of the robot relative to the hull when the robot is not being maneuvered using a switchable permanent magnetic fixation device independent of a drive subsystem of the robot.
 28. A system for autonomous hull robot navigation on a hull of a vessel independent of external guidance devices, comprising: a sensor onboard a hull robot and configured to detect an environmental characteristic; a database onboard the hull robot and configured to store information about the hull of the vessel, including correspondence information relating a position on the hull with the environmental characteristic detected by the sensor; a processor onboard the hull robot and configured to compare the detected environmental characteristic with the correspondence information in the database to determine the position of the hull robot on the hull.
 29. A method for fixing a position of a robot relative to a hull of a vessel when the robot is at rest, the method comprising: operating a hull robot about a hull of a vessel using a drive subsystem, the hull robot having a fixation device independent of the drive subsystem of the robot; and selectively actuating the fixation device to at least temporarily secure the robot in place about the hull.
 30. A hull robot, comprising: a robot body; a drive subsystem supported by the robot body for driving and maneuvering the robot about the hull of a vessel while the vessel is in motion in a fluid; structure in the robot for directing fluid flow about the hull into a specific fluid flow path within the robot body; a displacement energy extraction device supported by the robot body within the fluid flow path, and comprising a displaceable member moveable in response to the fluid flow acting upon the displaceable member, the displacement energy extraction device being configured to extract energy from the fluid flow useable by the hull robot.
 31. A hull robot comprising: a robot body; a drive subsystem supported by the robot body for driving and maneuvering the robot about the hull of a vessel while the vessel is in motion in a fluid; structure in the robot for directing fluid flow about the hull into a specific fluid flow path within the robot body; a displacement energy extraction device in the form of a propeller supported by the robot body within the fluid flow path, and comprising a displaceable member moveable in response to the fluid flow acting upon the displaceable member, the displacement energy extraction device being configured to extract energy from the fluid flow useable by the hull robot.
 32. A hull robot comprising: a robot body; a drive subsystem supported by the robot body for driving and maneuvering the robot about the hull of a vessel while the vessel is in motion in a fluid; structure in the robot for directing fluid flow about the hull into a specific fluid flow path within the robot body; a displacement energy extraction device comprising a water wheel supported by the robot body within the fluid flow path, and comprising a displaceable member moveable in response to the fluid flow acting upon the displaceable member, the displacement energy extraction device being configured to extract energy from the fluid flow useable by the hull robot.
 33. The robot of claim 32, wherein the water wheel comprises a plurality of blades disposed about a rotor of the water wheel.
 34. The robot of claim 32, wherein the water wheel comprises a plurality of fluid containers disposed about a rotor of the water wheel.
 35. A hull robot comprising: a robot body; a drive subsystem supported by the robot body for driving and maneuvering the robot about the hull of a vessel while the vessel is in motion in a fluid; structure in the robot for directing fluid flow about the hull into a specific fluid flow path within the robot body; a displacement energy extraction device comprising a flapper supported by the robot body within the fluid flow path, and comprising a displaceable member moveable in response to the fluid flow acting upon the displaceable member, the displacement energy extraction device being configured to extract energy from the fluid flow useable by the hull robot.
 36. A hull robot, comprising: a robot body; a drive subsystem supported by the robot body for driving and maneuvering the robot about the hull of a vessel while the vessel is in motion in a fluid; structure in the robot for directing fluid flow about the hull into a specific fluid flow path within the robot; an oscillation-based energy extraction device supported by the robot and within the fluid flow path, wherein the oscillation-based energy extraction device oscillates in response to the fluid flow acting upon the oscillation-based energy extraction device, the oscillation-based energy extraction device being configured to extract energy from the fluid flow useable by the hull robot.
 37. The robot of claim 36, wherein the oscillation-based energy extraction device comprises a flapper.
 38. The robot of claim 37, wherein the flapper is coupled to a rotating hinge and is oscillateable on the hinge.
 39. The robot of claim 37, wherein the flapper comprises a piezoelectric element and is oscillateable by flexing.
 40. A method of powering a hull robot, comprising: maneuvering the robot about the hull while the hull of a vessel while the vessel is in motion in a fluid; directing fluid flow about the hull into a specific fluid flow path within the robot toward a oscillation-based energy extraction device within the robot and within the fluid flow path, the oscillation-based energy extraction device being oscillateable in response to the fluid flow acting upon the oscillation-based energy extraction device; and extracting energy from the fluid flow with the oscillation-based energy extraction device, the energy being useable to provide to the hull robot.
 41. The method of claim 41, further comprising maintaining an orientation of the robot relative to the fluid flow to maximize energy harvested from the flow while driving and maneuvering the robot about the hull.
 42. The robot of claim 41, further comprising using the energy extracted from the fluid flow to power a cleaning subsystem of the hull robot to clean the hull of the vessel.
 43. The robot of claim 41, further comprising using the energy extracted from the fluid flow to power a drive subsystem of the hull robot to drive and maneuver the robot about the hull of the vessel.
 44. A hull robot, comprising: a robot body; a drive subsystem supported about the robot body for driving and maneuvering the robot about the hull of a vessel while the vessel is in motion in a fluid; an energy extraction device operable to extract energy from a fluid flow about the vessel, the fluid flow resulting from the motion of the vessel in the fluid; and a support structure for positioning and supporting the energy extraction device without the robot body, wherein the energy extraction device is in contact with the fluid flow outside the robot body.
 45. The robot of claim 44, wherein the energy extraction device is extendable from a position within the robot body to a position without the robot body, and wherein the energy extraction device is retractable.
 46. The robot of claim 44, wherein the support structure supports the energy extraction device in a position beyond a boundary layer of the fluid flow about the robot body.
 47. The robot of claim 44, wherein the energy extracted from the fluid flow is useable by the hull robot to clean the hull.
 48. The robot of claim 44, wherein the energy extracted from the fluid flow is useable by the drive subsystem to drive and maneuver the robot about the hull.
 49. The robot of claim 44, wherein the energy extraction device comprises a turbine.
 50. The robot of claim 44, wherein the displacement energy extraction device comprises a propeller.
 51. The robot of claim 44, wherein the displacement energy extraction device comprises a water wheel.
 52. The robot of claim 44, wherein the displacement energy extraction device comprises a flapper.
 53. A method of powering a hull robot, comprising: maneuvering the robot about the hull of a vessel while the vessel is in motion in a fluid; positioning an energy extraction device operable to extract energy from a fluid flow relative to a vessel without a body of the robot, the fluid flow resulting from the motion of the vessel in the fluid; extracting energy from the fluid flow with the energy extraction device, the energy being useable as power by the hull robot.
 54. The method of claim 53, further comprising retracting the energy extraction device from without the body of the robot to within the body of the robot to cease extracting the energy.
 55. The method of claim 53, further comprising retractably extending the energy extraction device from within the body of the robot to without the body of the robot to begin extracting the energy.
 56. The method of claim 53, wherein positioning the energy extraction device comprises positioning the energy extraction device beyond a boundary layer of the fluid flow about the body of the robot.
 57. The method of claim 53, further comprising cleaning the hull with the hull robot using the energy extracted from the fluid flow.
 58. The method of claim 53, further comprising driving and maneuvering the robot about the hull using the energy extracted from the fluid flow.
 59. A hull robot, comprising: a drive subsystem onboard the robot for driving and maneuvering the robot about a hull of a vessel; and a robot body having a longitudinal axis extending between longitudinal sides of the robot body and a lateral axis extending between lateral sides of the robot body, the drive subsystem being configured to drive the robot in a direction along the longitudinal axis; an inlet formed along at least one of the lateral sides of the robot body, wherein the robot is configured to travel about the hull of the vessel in a direction transverse to a surface of a fluid in which the vessel is operating.
 60. The robot of claim 59, further comprising: a fluid flow path within the robot body generated from fluid being received in the inlet; and an energy extraction device supported about the robot body and operable within the fluid flow path.
 61. The robot of claim 59, wherein the robot body comprises a hydrodynamic configuration tuned in a direction transverse to the longitudinal axis and a direction of travel of the robot, such that the hydrodynamics of the robot while being maneuvered in the direction of travel are enhanced.
 62. A hull robot, comprising: a drive subsystem onboard the robot for driving and maneuvering the robot about a hull of a vessel; a robot body comprising a hydrodynamic configuration tuned in a direction transverse to a longitudinal axis extending between longitudinal sides of the robot body, the longitudinal axis extending in a direction in which the robot is driven by the drive subsystem; wherein a fluid flow about the robot body resulting from motion of the vessel travels over the robot body in the tuned hydrodynamic direction to enhance efficiency of driving and maneuvering of the robot.
 63. The hull robot of claim 62, wherein the hydrodynamic configuration is tuned in a direction substantially parallel with a lateral axis extending between lateral sides of the robot body.
 64. The hull robot of claim 62, further comprising an inlet formed along a lateral side of the hull robot for receiving the fluid flow and for generating a fluid flow path within the robot body.
 65. The hull robot of claim 64, further comprising an energy extraction device operable within the fluid flow path.
 66. The hull robot of claim 65, wherein the energy extraction device is oriented in the tuned hydrodynamic direction.
 67. The hull robot of claim 71, wherein the lateral side extends between the longitudinal sides and is substantially orthogonal to the longitudinal sides.
 68. The robot of claim 62, wherein the robot body is symmetrical about at least a longitudinal axis and a lateral axis to facilitate enhanced efficiency bi-directional driving of the hull robot about multiple axes having different orientations.
 69. The robot of claim 62, wherein the robot body is radially symmetrical.
 70. A method of enhancing efficient operation of a hull robot about a hull of a vessel, comprising: configuring a robot body to comprise a hydrodynamic configuration tuned in a direction transverse to a direction of travel of the robot, and substantially in a direction of fluid flow resulting from motion of the vessel within a fluid; configuring a drive subsystem onboard the robot to maneuver the robot about a hull of a vessel in a direction transverse to a direction of the flowing fluid to enhance the efficiency of the fluid flow about the robot body.
 71. The method of claim 70, wherein the robot is maneuvered in a direction substantially orthogonal to the direction of the flowing fluid.
 72. The method of claim 70, further comprising employing an energy extraction device to extract energy from the fluid passing about the robot body.
 73. The method of claim 70, further comprising maneuvering the hull robot in a substantially bi-directional manner to avoid turning the hull robot around.
 74. The method of claim 70, further comprising maneuvering the hull robot up and down the hull of the vessel while moving from a front of the ship towards a back of the ship.
 75. The method of claim 70, further comprising configuring an inlet along a lateral side of the robot body, the inlet configured to receive a portion of the fluid therein and to generate a fluid flow path within the robot body.
 76. The method of claim 75, further comprising operatively positioning an energy extraction device within the fluid flow path.
 77. A method of enhancing efficient operation of a hull robot, comprising: configuring a hull robot to comprise a drive system operable to maneuver and drive the hull robot about a hull of a vessel along an axis extending from one of a top and bottom of the hull; configuring a robot body of the hull robot to comprise a longitudinal axis extending between longitudinal sides of the robot body and a lateral axis extending between lateral sides of the robot body, the drive subsystem being configured to drive the robot in a direction along the longitudinal axis; forming an inlet along at least one of the lateral sides of the robot body, wherein fluid received in the inlet generates a fluid flow path within the robot body; and providing an energy extraction device supported about the robot body, the energy extraction device being operably positioned within the fluid flow path.
 78. A hull robot, comprising: a robot body; a drive subsystem supported about the robot body for maneuvering the robot about a hull of a vessel; and a magnetic fixation device operable with the robot body and independent of the drive subsystem, the magnetic fixation device being actuatable to securely maintain a position of the robot relative to the hull when the drive subsystem is inactive.
 79. The hull robot of claim 78, wherein the drive subsystem comprises a magnetic device for attaching the robot body to the hull.
 80. The hull robot of claim 78, wherein the magnetic fixation device comprises a switchable magnet.
 81. The hull robot of claim 78, further comprising a plurality of magnetic fixation devices positioned about the robot body.
 82. The hull robot of claim 78, wherein the magnetic fixation device comprises an electromagnet.
 83. The hull robot of claim 78, wherein the magnetic fixation device comprises a permanent magnet.
 83. The hull robot of claim 78, wherein the magnetic fixation device restricts maneuvering of the robot by the drive subsystem when securely maintaining the position of the robot relative to the hull.
 85. The hull robot of claim 78, wherein the magnetic fixation device comprises a non-attachment configuration to enable the drive subsystem to maneuver the robot about the hull of the vessel when not securely maintaining the position of the robot relative to the hull.
 86. An autonomous hull robot navigation system for guiding a hull robot on a hull of a vessel independent of external guidance devices, comprising: a drive subsystem for driving and maneuvering the robot about a hull of a vessel; a paint sensor subsystem onboard the robot configured to sense a paint characteristic about the hull; a navigation subsystem onboard the robot and response to the paint sensor subsystem, being configured to facilitate navigation based on the paint characteristic.
 87. The robot of claim 86, wherein the paint characteristic comprises the presence or lack of paint.
 88. The robot of claim 86, wherein the paint characteristic comprises a freshness of a coat of paint.
 89. The robot of claim 86, wherein the paint sensor subsystem comprises a camera.
 90. A hull robot, comprising: a robot body; a drive subsystem supported by the robot body for driving and maneuvering the robot about the hull of a vessel while the vessel is in motion in a fluid; a cleaning subsystem supported by the robot body and having at least one cleaning element for cleaning the hull of the vessel; and an energy extraction device supported by the robot body, the energy extraction device being directly coupled to at least one of the drive subsystem and the cleaning element, wherein the energy extraction device is actuated by water passing over the hull of the vessel while the vessel is in motion.
 91. The hull robot of claim 90, wherein the energy extraction device comprises a direct mechanical connection to the drive subsystem.
 92. The hull robot of claim 90, wherein the energy extraction device supports one or more cleaning elements thereon, such that actuation of the energy extraction device functions to actuate a cleaning function by the energy extraction device. 